Outpatient Parenteral Antimicrobial Therapy (OPAT) for Infective Endocarditis in a Belgian Tertiary Care Center

Author(s): Helena C van den Hout, Isabel Spriet, Lotte Vander Elst, Melissa Depypere, Evelyn Hill, Marie- Christine Herregods, Charlotte Quintens, Liesbet Henckaerts

Aims: Treatment of infective endocarditis (IE) typically involves a long course of intravenous antibiotic therapy. Recognizing the increased emphasis on outpatient parental antibiotic therapy (OPAT) in the new 2023 ESC guidelines for IE, our aim is to evaluate our OPAT efficacy and safety in IE patients.

Methods and results: OPAT IE patients treated from July 2018 to December 2023 were included. Relevant demographic, clinical and microbiological data were collected. Outcomes were clinical cure at 3 months and OPAT- or IE-related readmission rates. A total of 70 OPAT episodes were performed in 69 patients with IE. Median age was 51,4 years (range 3-95 years), and 71% (n=49) of the patients were male. Prosthetic valve IE accounted for 50% of OPAT courses. Sixty-nine percent of patients needed cardiac surgery. Streptococci were the predominant causative organisms (63%), consequently, ceftriaxone was the most frequently used antibiotic (80%). Clinical cure 3 months after stopping OPAT was achieved in 67 of 70 episodes: two patients died unrelated to OPAT and one patient developed a reinfection one month after OPAT; readmission was necessary in 13 patients. Median duration of OPAT was 19 days (range 4-35), resulting in 1328 avoided hospitalization days.

Discussion: Consistent with previous studies, our OPAT program was effective and safe in selected patients. These data should be interpreted with caution given the stringent inclusion criteria, limited sample size, short OPAT duration and follow-up. In the future, we aim to provide a broader and earlier selection of patients, while maintaining a high clinical cure rate.